Extension-bolt.



P. H. GRUMP.

vLXTENSION BOLT. APPLICATION FILED UG. 18, 1908.

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FRANK H. CRUMP, F LOS ANGELES, CALIFORNIA.

EXTENSION-BOLT.

Specification of Letterslatent.

Patented Oct. 19, 1909.

Application led August 18, 1908. Serial No. 449,006.

4 To all whom t may concern:

Be it known that I, FRANK II. CRUMP, a citizen of the United States, and a resident of Los Angeles, in the county of Los Angeles and State of California, have invented certain new and useful Improvements in Extension-Bolts, of which the following is a specification.

My invention is an improvement in extension bolts for binding frames, and consists in certain novel constructions and combinations of parts hereinafter described and claimed.

Referring to the drawings forming a part hereof Figure 1 is a central longitudinal section of a portion of a bolt constructed in accordance with my improvement. Fig. 2 is a similar view of a complete bolt-y showing a modified form of head. Fig. 8 is a silnilar view showing another form of head. Fig. ,4: is a similar view of the bolt assembled, and Fig. 5 is an end view of the bolt shown in Fig. 1 with the segmental head removed.

The present embodiment of my invention comprises a bolt composed of a plurality of sections, an inner section A, an outer section B, and a shield or sleeve C. The section A is cylindrical and externally screw threaded as at a, and the head a is square for receiving a wrench, and is provided in the end thereof with a screw threaded opening a2, for receiving the threaded shank a3 of a head a4, which head is provided with a transverse kerf or slot a5 for receiving a screw-driver.

Between the head and the screw threaded portion a, of the section A, is an enlarged portion a6 externally screw threaded, and a shoulder c;7 is arranged between the head and the said enlarged portion. The outer section B (Fig. 2) is a hollow cylinder in.

ternally screw threaded as at b, andthe head b is cylindrical and provided with a 'transverse kerf or slot b2 for receiving a tool whereby to turn the section. rIhe shield C is a hollow cylinder having its lower end beveled as at c, and its upper end internally screw threaded as at c for engaging the threaded portion a, of the section A.

In Fig. 4f, the sections A, B, and the shield C are shown assembled, and it will be evident from an inspection of this figure that the shield C is threaded on to the enlarged portion a6 of the inner section A, the square end c2 of the shoulder engaging against the shoulder a7 before mentioned. The outer section B is received between the inner section A, and the shield C.

rThe inner section shown in Fig. 2 is similar to the inner section shown in Fig. l, eX-

cept that the head as is cylindrical and in Fig. 3 the head a9 is formed on the frustum of a cone, having its apex connected with the threaded portion, and its base provided with the slot or lrerf alo.

The extension D shown in Figs. l, 2 and 3 comprise a hollow cylinder having one end closed as at d, and provided with a threaded shank d for engaging within the external section B, and the cylinder is internally threaded as at d2, for receiving the inner section A. While only one extension is shown, it is evident that more might be made use of,

to extend the bolt to any length within reasonable limits.

It will be observed that in all of the bolts shown and described, the shield or sleeve C covers the threaded portion a, of the section A, at all times, to prevent engagement of the binder leaves with the said threaded portion.

The bolt head a is adapted for use with binding plate having a square hole. The plate is placed over the bolt, which will not turn, and the screw top al1 placed over the plate, thus retaining the extension plate firmly in place. rThe form of head shown in Fig. 2 is for plates having friction plates for engaging the head, and the head shown in Fig. 3 is for countersunk openings.

I claim.

l. An extension bolt comprising an outer section internally screw threaded, an inner section externally screw threaded, each of said outer and inner sections being provided with a head having means for engagement by a tool whereby to rot-ate the same, and said inner section having between the head and the threaded portion an enlarged threaded portion separated from the head by a shoulder, and a sleeve or shield comprising a hollow cylindrical portion encircling the.

and vthreaded on to the enlarged portion thereof, each of Said sections being provided with a head having means for engagement by a tool whereby to rotate the same.

3. An extension bolt comprising an inner section, externally screw threaded, an outer hollow internally screw threaded section into which the first section screws and a shield Comprising a hollow cylinder, encircling the inner section, and sliding over the outer section, said shield being threaded on to the inner section, each of said sections being provided with a head for the purpose set forth, a shoulder being formed between the head and the inner section and a screw threaded l portion for engagement by the end of the shield.

FRANK H. CRUMP.

Witnesses: l

L. J. MooNEY, P. HENNING. 

